This project aimed to understand the mechanism of HIV replication in cells, model animals and humans, clarify the nature of host response to HIV infection and develop strategies for controlling HIV infection and AIDS pathogenesis. Over 80 researchers participated in this project, which comprised of five subthemes ; 1) Mechanism of HIV replication, 2) Virological basis of pathogenesis, 3) Immunological basis of pathogenesis, 4) Development of animal models and 5) Control of infection and pathogenesis. Their researches in three years period were able to reveal novel features of interactions of viral proteins with cellular components in HIV life cycle and identify viral genome changes, host proteins and genetic polymorphism that were likely specific for or associated with disease progression. Outcomes of the research also included the identification cytotoxic T cell epitopes crucial for antiviral state and development of animal models such as the trasgenic and SCID/hu mice and the monkey model, which allowed evaluation of HIV infection and pathogenesis. Efforts were also made to design and develop therapeutic compounds for AIDS. Several novel candidate compounds of high potential were created. These outcomes represent a significant contribution to the understanding and control of HIV/AIDS pathogenesis. Important research topics in future are further clarification of genetic and immunological background underlying susceptibility/resistance and disease progression by analyzing high risk/uninfected populations as well as long term nonprogressors. It is also important to learn how once destroyed immunological functions would be reconstructed in AIDS patients during highly active antiretroviral therapy.